A highly sensitive temperature and strain sensor cascaded with a fiber Lyot filter (FLF) and a fiber Sagnac interferometer (FSI) is proposed in this paper. The temperature and strain characteristics of Lyot filter without and with Vernier effect are experimentally studied. Because the free spectral ranges (FSRs) of the two interferometers can be controlled simply by adjusting the length of polarization-maintaining fiber (PMF), the Vernier effect can be realized conveniently. High temperature and strain sensitivity measurement is obtained by this structure for the first time. The experimental results indicate that the temperature and strain sensitivity of the cascade structure can reach -61.52 nm/degrees C and 58.63 pm/mu epsilon respectively, which is about 50 times higher than that of a single FLF whose temperature and strain sensitivity is 1.23 nm/degrees C and 1.21 pm/mu epsilon. By carefully optimizing the structural parameter, the sensitivity can be further improved, which provides a new choice for temperature and strain detection.
展开▼
